Did a Comet Kill the Woolly Mammoths?

Could a comet have caused the extinction of North America’s megafauna—woolly mammoths, giant ground sloths, and saber-tooth tigers?

James Kennett, professor emeritus in the University of California, Santa Barbara, department of Earth science, posits that such an extraterrestrial event occurred 12,900 years ago.

Originally published in 2007, Kennett’s controversial Younger Dryas Boundary (YDB) hypothesis suggests that a comet collision precipitated the Younger Dryas period of global cooling, which, in turn, contributed to the extinction of many animals and altered human adaptations.

The nanodiamond is one type of material that could result from an extraterrestrial collision, and the presence of nanodiamonds along Bull Creek in the Oklahoma Panhandle lends credence to the YDB hypothesis.

More recently, another group of earth scientists, including UC Santa Barbara’s Alexander Simms and alumna Hanna Alexander, re-examined the distribution of nanodiamonds in Bull Creek’s sedimentological record to see if they could reproduce the original study’s evidence supporting the YDB hypothesis. Their findings appear in the Proceedings of the National Academy of Sciences.

“We were able to replicate some of their results and we did find nanodiamonds right at the Younger Dryas Boundary,” says Simms, an associate professor in the department of Earth science. “However, we also found a second spike of nanodiamonds more recently in the sedimentary record, sometime within the past 3,000 years.”

The researchers analyzed 49 sediment samples representing different time periods and environmental and climactic settings, and identified high levels of nanodiamonds immediately below and just above YDB deposits and in late-Holocene near-surface deposits.

The late Holocene began at the end of the Pleistocene 11,700 years ago and continues to the present. The researchers found that the presence of nanodiamonds is not caused by environmental setting, soil formation, cultural activities, other climate changes, or the amount of time in which the landscape is stable.

The discovery of high concentrations of nanodiamonds from two distinct time periods suggests that whatever process produced the elevated concentrations of nanodiamonds at the onset of the Younger Dryas sediments may have also been active in recent millennia in Bull Creek.

“Nanodiamonds are found in high abundances at the YDB, giving some support to that theory,” Simms says. “However, we did find it at one other site, which may or may not be caused by a smaller but similar event nearby.”

A “recent” meteorite impact did occur near Bull Creek but scientists don’t know exactly when. The fact that the study’s second nanodiamond spike occurred sometime during the past 3,000 years suggests that the distribution of nanodiamonds is not unique to the Younger Dryas.

Read the original on Futurity.org. Republished under Creative Commons license 3.0.

*Illustration of woolly mammoths via Shutterstock

  • http://www.imallwrite.com/ drewbai

    There once were some Mamoths most Woolly
    Whose extinction happened most fully
    A comet descended
    Their time here was ended
    The universe can be such a bully!

    • chenelope

      There now are humans most advanced,
      Who think with the brains in their pants,
      With morality eroding,
      And disaster foreboding,
      They’ve left an awful lot to chance.

  • Denni A

    my understanding is around 10,000 yrs ago, during the most recent ice age, humans crossed the Bering Straits from the Asian continent to the North American continent and began systematically wiping out the large species of animals on the continent.
    is there any scientific evidence of comet debris from the last 10,000 yrs.

  • againstitall

    Bill Hayleys band are innocent.

  • VincentTPackhorse

    “James Kennett, professor emeritus in the University of California, Santa Barbara, department of Earth science, posits that such an extraterrestrial event occurred 12,900 years ago.”

    A small semantic quibble: if a comet were to strike the moon or the planet Jupiter, that would constitute an extraterrestrial event. If a comet were to strike the Earth, would not that be considered a terrestrial event even though the impinging object were of extraterrestrial origin?

    • Xiccarph

      It would have been more correct if he’d said “…an event of extraterrestrial origin occurred 12,900 years ago.” But hey, he’s a prof, and in southern CA. Be thankful they still use English there at all!

  • takawalk

    A question for those more informed than me. Why is it not assumed that the Mammoth evolved into the Elephant? Sorry for my ignorance on the topic.

    • Denni A

      asking questions is never a sign of ignorance, not asking questions keeps one forever ignorant imo.

      seems the Mammoth, Asian and African Elephant have a common ancestor from 6 million years ago. I would imagine the ancestor originated in Africa, much like the human/simian species, and the ancestor migrated to Asia and evolved into the Asian Elephant, my question would be how did that ancestor arrive on the North American continent then evolve into the woolly Mammoth. I would think it developed it’s woolly hair to keep warm in the coming ice ages after it arrived.

  • Raymond Chuang

    Only one thing though: has scientists around the world found unusual sedimentary deposits in the soil around the world dated circa 12,500 BC? We know of the meteor impact from 65 million years ago because of the discovery of unusual minerals in the rocks that date from around that time.

  • Ed C

    It makes more sense that humans hunted these large animals to extinction. Why not? They were a good food source and their tusks made for really wicked weapons and symbols of power within the clan after all. Look at what is happening now to the African Elephant. They are being exterminated for their Ivory.